1. Field of the Invention
This invention relates to an apparatus for quick discharging ink from an ink supply device of a printing machine, and more particularly, to an ink reserve vessel of an ink supply section of the ink fountain type including, in addition to the ink reserve vessel called ink fountain or ink pan, an ink transfer medium called fountain roller for taking out ink by being partly soaked in ink held in the ink reserve vessel, and to an ink supply device.
2. Description of the Prior Art
Conventional ink supply devices of the foregoing type are of the two-stage system which is featured in that an ink tank is provided on the back side of an ink reserve vessel for storing a comparatively large quantity of ink, ink being supplied is once stored in the ink tank, and then an adequate quantity of ink is supplied bit by bit from the ink tank through a pipe to the ink reserve vessel (see Japanese Patent Publication Nos. 35-12862, 39-5717 and 59-393).
Specifically, conventional ink supply devices of the foregoing system are designed, without considering the case of quick discharging of ink in the course of printing, such that an adequate quantity of ink is continuously supplemented from the ink tank to the ink reserve vessel and the thus supplemented ink held in the reserve vessel is supplied to a plate drum by means of an ink transfer medium. Therefore, as far as the conventional devices are used in a mode where the supply direction of ink is not disturbed, there occurs no inconvenience.
On the other hand, it has been found that although the quality of printing cannot be improved if the ink is supplied at room temperature as in the prior art, it can be remarkably enhanced if the ink being supplemented to the ink fountain is supplied, during the whole period of printing, with a substantially uniform physical property which is restored when the ink is heated to a specified temperature. When putting the foregoing discovery into practice, since the ink held in the ink reserve vessel has no desired temperature with its physical property having changed at the moment when the printing machine is going to restart after a long interval of down time, all ink of low temperature remaining in the ink fountain must be quickly returned into the ink tank.
For example, when a change of the fountain roller is desired to be made to deal with the occurrence of some inconvenient situation, it is required to quickly discharge the ink held in the reserve vessel and to fill the reserve vessel with new one.
To cope with such a case, as shown in FIG. 5, the conventional machine has only an ordinary discharge hole 2f bored at one bottom corner of an ink reserve vessel 2. When viscous ink is allowed to discharge through such a hole, it takes a long interval of time until the completion of discharging; thus, the work of printing is delayed correspondingly.
As another measure of solving the foregoing problem, one may consider discharging the ink by detaching the ink reserve vessel from its attaching frame; but, this procedure needs much labor and time in detaching and discharging, and mental fatigue is appreciably imposed on workers doing such dirty work.